Magnetic speed-indicator.



No. 680,988. Patented Aug. 205 I90I.

S. B. STORER.

MAGNETIC SPEED INDICATOR.

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N0. 680,938. Patented Allg. 20, |90l. S. B. STORER. Y MAGNETIC SPEEDHDICTUB.

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UNITED STATES PATENT OEEICEo SIMON B. STORER, OF SYRAOUSE, NEW YORK.

`MAGNETIC SPEED-INDICATOR.

ISPECIFIC.A'TIO forming part of Letters Patent No. 680,988, dated August20, 1901.

Application filed March 14, 1900. Serial No. 8,648. (No model.)

To all whom it may concern.-

Beit known that I, SIMON B. SToRER, a citizen of the United States, anda resident of lbetween the poles.

Syracuse, in the county of Onondaga and State of New York, have inventedcertain new and useful Improvements in Magnetic Speed- Indicators, ofwhich the following is a specication.

The object of my invention is to produce a magnetic speed or velocityindicator which shall be of a size and weight to make it readilyportable and yet be powerful and accurate and at the same time giveuniform results under varying conditions of use.

Magnetic speed-indicators have been previously devised. They depend uponthe pull which moving permanent magnets exert on a copper disk biased toa normal position of rest, the movement of the magnets causing adisplacement of the disk from its normal position of bias by an amountproportional to the speed of the magnets movement. The construction ofsuch indicators has required that the permanent or energizing magnets bemovable-that is, either revoluble or oscillatory. Again, such permanentmagnets were inefficient and not suitable for giving the most powerfulresults because of the shape it was necessary to give to them. By reasonof the movability of the permanent magnet and its inefficiency it hasheretofore been found necessary to make magnetic speed-indicators verylarge in order to produce an appreciable effect, which means thatindicators embodying such movable permanent magnets have either beenvery heavy and cumbersome or inefficient.

In a speed-indicator constructed in accordance with my invention thepermanent or energizing magnet is no longer movable, but becomes astationary field-magnet. Besides, it is given a form, preferably, withconcentric annular poles, which is adapted to give the most powerfuleffect-s. Within the field of this permanent or field magnet I mount asoft iron or steel keeper or armature, which is movable,-and which incase the field-magnet has annular concentric poles I make in the form ofa cylinder moving in the space This armature I furthermore make oftoothed or other irregular shape, .so as to cause a bunching or tuftingof the lines of force in the magnetic iield within which the armaturemoves. In juxtaposition to the armature I mount a movable part,preferably of low and constant electrical resistance or made of copper,German silver, or the like. Thus I use a copper or other low-resistancecylinder concentric'with the cylindrical armature when I employ afield-magnet of the type above referred to, in which the poles areconcentric and annular. I may now either make the soft iron or steelarmature revoluble and the low-resistance partoscillatory or I may havethe armature oscillate and the low-resistance part revolve. In eithercase the oscillatory part is biased to a normal position of rest by aspring or springs. Assuming that the soft iron or steel armature isrevoluble and that it is revolved through suitable gearing by the partthe speed of which it is desired to measure, I have found that therevolution of the armature by reason of the lines of force which itdrags along with it will exert a pull upon the oscillatorylow-resistance part which is in proportion to the speed of rotation.This oscillatory part being biased to remain in a normal position by aspring the reaction of which under different displacements is reasonablyconstant, it becomes plain that the oscillatory part will be displacedfrom its normal position by an amount which is proportional to the speedof the moving part, and assuming the existence of `a proper scale thespeed of the moving part may be at once read from the instrument. It ispreferable to have the soft iron or steel armature oscillate and thelow-resistance part revolve. This will do away with the eddy-currentloss in the faces of the permanent magnet, which might become a sourceof error in case the soft-iron armature were revolved at high speed.Besides, I am enabled in this form to use a copper or otherlow-resistance shield placed in a fixed position close to the soft-ironarmature, so as to act as a damper against any sudden acceleration ofthe oscillating armature. The instrument thus becomes dead-beat.

In the drawings, Figure lisa central section of one form of indicator;Fig. 2, acentral section taken at right angles thereto. Fig. 3 is a planof the same form of indicator. Fig. 4 is a plan of another form ofindicator. Fig. 5 is IOO a cross-section 'of the modified form shown linFig. 41 Fig. 6 is a perspective of the pair of spiral springs, and Fig.7 is a detail of the indicator.

The energizing or iield magnet, which has been shown as a permanentmagnet, but which might also be an electromagnet, has a central pole Aand a surrounding concentric cylindrical pole B, with a field of forcein the space between the poles. This form of field-magnet is mostefficient, being at once powerful and compact. It is', however, not theonly form which I may employ.

The soft-iron armature c has been shown of cylindrical form,accommodating itself to the space between the Iield-poles A and B.Naturally if the shape of the ield-poles is varied the shape of thearmature c will be varied correspondingly. The armature is formed withteeth o' or other irregularities of shape or structure in order to tuftor bunch the lines of force of the field, and it is mounted on an armedspider c2, and thereby secured in a fixed fashion to the hollow shaft H.To the shaft I-I are secured cones H, which rest against ball-bearingsL. A gear-wheel G is fastened to the shaft H, and a second gearwheel Gmeshes therewith in order to drive it. A key T or other suitable device,such as a pulley or wheel, being connected with the gear G', it ismanifest that if the key T is pressed against a rotary part whose speedis to be measured, such as a shaft, the rotation of the shaft will becommunicated through the parts T G G H to the armature c, causing it torotate with an angular velocity proportional to that of the shaft orpart whose speed is to be measured. The key T, as shown, has aspear-head the point of which is pressed against the axial center at theend of the rotating shaft whose speed is to be measured. Generally, theprojecting ends of shafts of machines have countersinks, made in turningup the shaft, into which this spearhead will lit. 'Ihe low-resistancepart d is shown as a cylinder concentric with and corresponding` inshape to the armature c and field-poles. It is mounted by arms d on aspindle E. The spindle rests in steps P, one of which is secured in abracket S and the other of which is formed in a post P', thatis threadedinto the bracket S, .Which bracket also serves as a support for thespindle of the gear G. Two spiral springs F F', oppositely wound, haveone of their ends each secured to the spindle E and their other endssecured ro some fixed part of the device, such as the bracket S'. Thesesprings give the oscillatory part d a bias to return to a fixed normalposition. Should the indicator be so used that the part d always tendsto move in a given direction, one of the springs F F may be omitted. Forconvenience of illustration these springs have not been shown in theplan views. There is a slot R cut into the outer polo of thefield-magnet, so as to permit the extent of the displacement of part dto be observed. v

The operation of the speed-indicator (shown in Figs. 1 and 3) will nowbe clear. The'part the oscillatory T or the like being pressed againstthe movythe oscillatory low-resistance part d, the

amount o1 which pull is proportional to the speedV of rotation of thearmature c. The os cillatory part d will therefore be displaced from itsnormal position until the reaction of the spring F, tending to ret-urnit to the.

normal position, is precisely balanced; but

as the force exerted by the spring is about proportional to thedisplacement of the part d and as thepull of the armature on the part dis about proportional to its speed it follows that the displacement ofthe oscillatory part d from its normal position of rest is proportionalto the speed of the moving part. By having the outer face of the part dproperly graduated `this speed can at once be read through the apertureR. It' so desired, the outer face may be graduated in miles per hour toadapt it for use on railway-trains or other moving Vehicles.

In the construction of Fig. 4 the armature c is mounted on a partcorresponding to the spindle E-Y'that is to say, the armature c ismounted to oscillate. On the other hand, the low-resistancepart CZ ismounted on a part corresponding to the shaft H-that is, it is mounted torevolve. In this case the rotary low-resistance part will drag along theoscillatory soft iron or steel armature, which has a normal position ofrest. By reading the amount of displacement of the oscillatory armaturethrough the slot R the speed is determined. I may call attention to thecopper or other shield n which is used in this construction and whichclosely embraces the inner pole A of the field-magnet and which acts toprevent any sudden acceleration of the armature c.

The com pactness and magnetic strength of my indicator cannot beoverlooked. I have provided a pair of field-poles which act upon eachportion or element of my armature and low-resistance part. The advantageof suoli' construction over those using a number of small movablehorseshoe-magnets,where each magnet merely actsupon aportion ofthemoving parts, is apparent.

I have not thought it necessary toshow the surrounding case for thisindicator, nor have I shown the graduation on the moving part, fromwhich the speed may be directly read. So, too, although I have shown oneform of indicator in which the armature os-illates and another form inwhich the armaturerevolves I have shown in each case the armature as acylinder; but it will be understood IOO IIO

while this is the preferred form that it is not the only form or shapewhich my armature and the parts coperating therewith may assume. Again,I have shown the armature with teeth for bunching the lines of force;but manifestly any irregularity in shape or structure might be usedinstead of these teeth.

What I claim isl. A magnetic speed-indicator comprising a field-magnet,a movable armature and a movable low-resistance part both mounted to becut by the same lines of force of the common field, one of the movableelements being revoluble and acting to drag along the other elementwhich is oscillatory, and a mechanical biasing device for theoscillatory element, substantially as described.

2. A magnetic speed-indicator comprising a field-magnet havingconcentric poles, a movable armature and movable low-resistance partwithin its field, one of the movable elements being revoluble, and theother being oscillatory but biased to a normal position of rest,substantially as described.

3. A magnetic speed-indicator comprising a iieldmagnet having concentricannular poles and a movable cylindrical armature and a movablecylindrical low-resistance part both within its field, one of themovable elements being revoluble and the other being oscillatory butbiased to a normal position of rest, substantially as described.

4. A magnetic speed-indicator comprising a fieldmagnet having`concentric annular poles and a movable cylindrical toothed armature anda movable cylindrical low-resistance part both within its field, one ofthe movable elements being revolu ble and the other being oscillatorybut biased to a normal position of rest, substantially as described.

5. A magnetic speed-indicator comprising a field-magnet havin gconcentric poles, a movable armature and movable low-resistance partwithin its field, a hollow rotary shaft for supporting one of themovable elements and an oscillatory spindle within the hollow shaftbiased to a normal position of rest and supporting the other movableelements, substantially as described.

G. A magnetic speed-indicator comprising a field-magnet havingconcentric poles, a movable armature and movable low-resistance partWithin its field, a hollow rotary shaft for supporting one of themovable elements,

ball-bearin gs for supporting the shaft, an oscillatory spindle withinthe hollow shaft supporting the other movable elements, and a spring orsprings for giving the spindle a bias to a normal position of rest,substantially as described.

7. A magnetic speed-indicator comprising a field-magnet havingconcentric poles, and an oscillatory armature biased to a normalposition of rest, and a revoluble low-resistance part both moving withinits field, substantially as described.

S. A magnetic speed-indicator comprising a field magnet havingconcentric annular poles and an oscillatory cylindrical armature biasedto a normal position of rest and a revoluble low resistance cylindricalpart both moving Within its field, substantially as described.

9. A magnetic speed-indicator comprising a field-magnet, having anoscillatory armature mechanically biased to a normal position of restand a revoluble low-resistance part which acts to drag along theoscillatory armature, both parts mounted to move in the common field ofthe magnet, substantially as described.

lO. A magnetic speed-indicator comprising a field-magnet having anoscillatory armature mechanically biased to a normal position of restand arevoluble low-resistance part to drag along the armature, bothmoving within its common field and a stationary electrical shield injuxtaposition to the armature, substantially as described.

11. A magnetic speed-indicator comprising a field-magnet, a movablearmature and a movable low-resistance part, one of the movable elementsbeing revoluble and acting inductively upon the other element which isoscillatory but mechanically biased to a normal position of rest todragit along, substantially as described.

`l2. A magnetic speed-indicator comprising a field-magnet, having anoscillatory armature mechanically biased to a normal position of restand a revoluble low-resistance part acting inductively upon the armatureto drag it along, substantially as described.

In testimony whereof I have signed my name to this specification in thepresence of two subscribing witnesses.

SIMON B. STORER.

lVitnesses:

LoUrs W. EMERIOK, Gnoncn W. PULvEn,

IOO

